Fix error when checking if IP address is valid

During install in `valid_ip`, we split up the IP address into octets to verify it is valid (each is <= 255).

This validation was broken in #2743 when a variable usage was quoted where it should have stayed unquoted:
```
./automated install/basic-install.sh: line 942: [[: 192.241.211.120: syntax error: invalid arithmetic operator (error token is ".241.211.120")
```

Due to this error, `127.0.0.1` would be used instead of the requested IP address. Also, this prevented the user from entering a custom DNS server as it would be marked as an invalid IP address.

Signed-off-by: Mark Drobnak <mark.drobnak@gmail.com>

automated install/basic-install.sh

@@ -934,7 +934,7 @@ valid_ip() {
         # and set the new one to a dot (period)
         IFS='.'
         # Put the IP into an array
-        ip=("${ip}")
+        ip=(${ip})
         # Restore the IFS to what it was
         IFS=${OIFS}
         ## Evaluate each octet by checking if it's less than or equal to 255 (the max for each octet)